@article{oai:repo.qst.go.jp:00048608,
 author = {Matsumoto, Ken-ichiro and Nyuui, Minako and Kamibayashi, Masato and Ozawa, Toshihiko and Nakanishi, Ikuo and Anzai, Kazunori and 松本 謙一郎 and 乳井 美奈子 and 上林 將人 and 小澤 俊彦 and 中西 郁夫 and 安西 和紀},
 issue = {1},
 journal = {Journal of Clinical Biochemistry and Nutrition},
 month = {Dec},
 note = {Temperature-dependent free radical reactions were investigated using nitroxyl radicals as redox probes. Reactions of two types of nitroxyl radicals, TEMPOL (4-hydroxyl-2,2,6,6-tetramethylpiperidine-N-oxyl) and carbamoyl-PROXYL (3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl), were tested in this paper. Heating a solution containing a nitroxyl radical and a reduced form of glutathione (GSH) caused temperature-dependent decay of electron paramagnetic resonance (EPR) signal intensity of the nitroxyl radical. Heating a solution of the corresponding hydroxylamine form of the nitroxyl radical showed EPR signal recovery. The GSH-dependent reduction of nitroxyl radicals at 70[Deg]C was suppressed by antioxidants, spin trapping agents, and/or bubbling N2 gas, although heating carbamoyl-PROXYL with GSH showed temporarily enhanced signal decay by bubbling N2 gas. Since SOD could restrict the GSH-dependent EPR signal decay of TEMPOL, O2- is related with this reaction. O2- was probably generated from dissolved oxygen in the reaction mixture. Oxidation of the hydroxylamines at 70[Deg]C was also suppressed by bubbling N2 gas. Heating a solution of spin trapping agent, DMPO (5,5-dimethyl-1-pyrroline-N-oxide) showed a temperature-dependent increase of the EPR signal of the hydroxyl radical adduct of DMPO. Synthesis of hydroxyl radical adduct of DMPO at 70[Deg]C was suppressed by antioxidants and/or bubbling N2 gas. The results suggested that heating an aqueous solution containing oxygen can generate reactive oxygen species, mainly O2-.},
 pages = {40--46},
 title = {Temperature-Dependent Free Radical Reaction in Water},
 volume = {50},
 year = {2011}
}